MONTPELIER — Lawmakers could again be on a collision course with Gov. Peter Shumlin as they seek information about a state division responsible for investigating cases of abuse against elderly residents.

The screeners staffing the phones at Adult Protective Services last year fielded 1,829 allegations of abuse, neglect or exploitation of an elder. But they referred fewer than half to investigators. And lawmakers say they want more information about the protocols being used to determine whether a complaint merits follow-up.

“This is the body that decides whether the policy that’s in place works,” said Rep. Sandy Haas, a Rochester Progressive and vice chairwoman of the House Committee on Human Services. “And we cannot do our job if we don’t have enough information.”

The House on Thursday gave final approval to legislation that would require the Department of Disabilities, Aging and Independent Living to file quarterly reports enumerating the reasons complaints are not investigated.

Gov. Peter Shumlin vetoed a similar bill last year and said last week that his concerns remain. Adding new reporting requirements to the workload of state employees, he said, will only distract them from their mission.

“What I don’t want to see in government is having my hardworking state employees spending more time filling out forms and sending reports than they are serving customers,” Shumlin said. “I don’t think adding a layer of bureaucracy to the process does anything to serve those vulnerable clients.”

Adult Protective Services came under a microscope early last year when advocates filed a lawsuit alleging the state had breached its statutory responsibility to protect vulnerable adults. Administration officials said the backlog of complaints that spawned the suit predated Shumlin’s inauguration. Shumlin said the staff and resources added to the division under his watch have eliminated the backlog and improved victim services.

“We were understaffed. We weren’t getting through the backlog as quickly as we wished we could have, and people weren’t being served the way we wished they could be served,” Shumlin said. “We fixed that. We hired the folks, we got through the backlog, and we’re doing a good job now of ensuring we don’t have seniors living in situations where they might be abused without having a response.”

Haas said that by all accounts, Adult Protective Services is functioning more effectively now than it was when the lawsuit was filed last year. However, she said the rate at which complaints are being investigated raises flags.

And among the cases that are investigated, she said, the rate at which the allegations are “substantiated” by the state is among the lowest in the nation.

Haas said the issue of elder abuse assumes heightened importance as older Vermonters stay in their homes longer. Whereas elder abuse was formerly concentrated in the institutional settings where many seniors used to be housed, Haas said the population is now more geographically scattered, making abuse harder to detect and resolve.

The commissioner of Disabilities, Aging and Independent Living, Susan Wehry, said two main reasons cases are closed at the time of the initial screening are that the person doesn’t meet the statutory definition of a vulnerable adult, or the alleged violation doesn’t constitute the abuse, neglect or exploitation needed to launch an investigation.

She said some cases also involved “self-neglect,” something for which Adult Protective Services can make a referral, but not something its staff is authorized to investigate.

Wehry said the bill passed by the House this year is far less burdensome than the version Shumlin vetoed last year. She said she still hasn’t had a chance to talk with the governor about the newest version.

But she said she’ll tell him she thinks it’s unnecessary, as her department is already collecting the information that lawmakers seek.

Lawmakers disagree and say they’ll continue to push for reports that will help one of the grayest states in the nation protect its older residents from abuse.